[flang] convert program name to upper case (NFC) (#149508)

Author: kkwli

flang/test/Semantics/PowerPC/ppc-vector-types01.f90

@@ -1,7 +1,7 @@
 ! RUN: %flang_fc1 -fdebug-unparse %s | FileCheck %s
 ! REQUIRES: target=powerpc{{.*}}
 
-    ! CHECK-LABEL: PROGRAM ppc_vec_unit
+    ! CHECK-LABEL: PROGRAM PPC_VEC_UNIT
       program ppc_vec_unit
       implicit none
       ! CHECK: VECTOR(INTEGER(KIND=4_4)) :: vi1, vi2

flang/test/Semantics/PowerPC/ppc-vector-types02.f90

@@ -2,7 +2,7 @@
 ! REQUIRES: target=powerpc{{.*}}
 
 ! C: MainProgram scope: ppc_vec_types
-! CHECK-LABEL: MainProgram scope: ppc_vec_types size={{[0-9]*}} alignment={{[0-9]*}}
+! CHECK-LABEL: MainProgram scope: PPC_VEC_TYPES size={{[0-9]*}} alignment={{[0-9]*}}
 program ppc_vec_types
   implicit none
   vector(integer(4)) :: vi