Avoid constprop in syevd! and syev! (JuliaLang#56442)

This improves compilation times slightly:
```julia
julia> using LinearAlgebra

julia> A = rand(2,2);

julia> @time eigen!(Hermitian(A));
  0.163380 seconds (180.51 k allocations: 8.760 MiB, 99.88% compilation time) # master
  0.155285 seconds (163.77 k allocations: 7.971 MiB, 99.87% compilation time) # This PR
```
The idea is that the constant propagation is only required to infer the
return type, and isn't necessary in the body of the method. We may
therefore annotate the body with a `@constprop :none`.

Author: jishnub

stdlib/LinearAlgebra/src/lapack.jl

@@ -5318,6 +5318,14 @@ solution `X`.
 """
 hetrs!(uplo::AbstractChar, A::AbstractMatrix, ipiv::AbstractVector{BlasInt}, B::AbstractVecOrMat)
 
+for f in (:syevd!, :syev!)
+    _f = Symbol(:_, f)
+    @eval function $f(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix)
+        W, A = $_f(jobz, uplo, A)
+        jobz == 'V' ? (W, A) : W
+    end
+end
+
 # Symmetric (real) eigensolvers
 for (syev, syevr, syevd, sygvd, elty) in
     ((:dsyev_,:dsyevr_,:dsyevd_,:dsygvd_,:Float64),
@@ -5329,7 +5337,7 @@ for (syev, syevr, syevd, sygvd, elty) in
         #       INTEGER            INFO, LDA, LWORK, N
         # *     .. Array Arguments ..
         #       DOUBLE PRECISION   A( LDA, * ), W( * ), WORK( * )
-        Base.@constprop :aggressive function syev!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
+        Base.@constprop :none function _syev!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
             require_one_based_indexing(A)
             @chkvalidparam 1 jobz ('N', 'V')
             chkuplo(uplo)
@@ -5350,7 +5358,7 @@ for (syev, syevr, syevd, sygvd, elty) in
                     resize!(work, lwork)
                 end
             end
-            jobz == 'V' ? (W, A) : W
+            W, A
         end
 
         #       SUBROUTINE DSYEVR( JOBZ, RANGE, UPLO, N, A, LDA, VL, VU, IL, IU,
@@ -5429,7 +5437,7 @@ for (syev, syevr, syevd, sygvd, elty) in
         # *     .. Array Arguments ..
         #       INTEGER            IWORK( * )
         #       DOUBLE PRECISION   A( LDA, * ), W( * ), WORK( * )
-        Base.@constprop :aggressive function syevd!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
+        Base.@constprop :none function _syevd!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
             require_one_based_indexing(A)
             @chkvalidparam 1 jobz ('N', 'V')
             chkstride1(A)
@@ -5459,7 +5467,7 @@ for (syev, syevr, syevd, sygvd, elty) in
                     resize!(iwork, liwork)
                 end
             end
-            jobz == 'V' ? (W, A) : W
+            W, A
         end
 
         # Generalized eigenproblem
@@ -5526,7 +5534,7 @@ for (syev, syevr, syevd, sygvd, elty, relty) in
         # *     .. Array Arguments ..
         #       DOUBLE PRECISION   RWORK( * ), W( * )
         #       COMPLEX*16         A( LDA, * ), WORK( * )
-        Base.@constprop :aggressive function syev!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
+        Base.@constprop :none function _syev!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
             require_one_based_indexing(A)
             @chkvalidparam 1 jobz ('N', 'V')
             chkstride1(A)
@@ -5550,7 +5558,7 @@ for (syev, syevr, syevd, sygvd, elty, relty) in
                     resize!(work, lwork)
                 end
             end
-            jobz == 'V' ? (W, A) : W
+            W, A
         end
 
         #       SUBROUTINE ZHEEVR( JOBZ, RANGE, UPLO, N, A, LDA, VL, VU, IL, IU,
@@ -5639,7 +5647,7 @@ for (syev, syevr, syevd, sygvd, elty, relty) in
         #       INTEGER            IWORK( * )
         #       DOUBLE PRECISION   RWORK( * )
         #       COMPLEX*16         A( LDA, * ), WORK( * )
-        Base.@constprop :aggressive function syevd!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
+        Base.@constprop :none function _syevd!(jobz::AbstractChar, uplo::AbstractChar, A::AbstractMatrix{$elty})
             require_one_based_indexing(A)
             @chkvalidparam 1 jobz ('N', 'V')
             chkstride1(A)
@@ -5673,7 +5681,7 @@ for (syev, syevr, syevd, sygvd, elty, relty) in
                     resize!(iwork, liwork)
                 end
             end
-            jobz == 'V' ? (W, A) : W
+            W, A
         end
 
         #       SUBROUTINE ZHEGVD( ITYPE, JOBZ, UPLO, N, A, LDA, B, LDB, W, WORK,