[NFC fix] merge FIRRuntime in FIRBuilder to break circular deps - part 1

Simply move the files without any change so that git can keep track of the
rename. CMakeLists.txt are updated. Other changes required to get in a buildable
state will be in a part 2 commit.

Author: jeanPerier

flang/include/flang/Optimizer/Runtime/Assign.h renamed to flang/include/flang/Optimizer/Builder/Runtime/Assign.h

@@ -24,7 +24,6 @@ add_flang_library(FortranLower
   FIRDialect
   FIRSupport
   FIRTransforms
-  FIRRuntime
   ${dialect_libs}
   omp_gen
   acc_gen
@@ -34,7 +33,6 @@ add_flang_library(FortranLower
   FIRDialect
   FIRSupport
   FIRTransforms
-  FIRRuntime
   ${dialect_libs}
   FortranCommon
   FortranParser

flang/include/flang/Optimizer/Runtime/Character.h renamed to flang/include/flang/Optimizer/Builder/Runtime/Character.h

@@ -7,6 +7,12 @@ add_flang_library(FIRBuilder
   DoLoopHelper.cpp
   FIRBuilder.cpp
   MutableBox.cpp
+  Runtime/Assign.cpp
+  Runtime/Character.cpp
+  Runtime/Derived.cpp
+  Runtime/Numeric.cpp
+  Runtime/Reduction.cpp
+  Runtime/Transformational.cpp
 
   DEPENDS
   FIRDialect