build-llvm: Bump to the final 14.0.0 release

Compared with RC2, the only notable change for mingw targets is
that sections named .debug_* are sorted to the very end of the
image, after any other discardable sections, avoiding leaving gaps
if stripping such executables. (This can affect rust binaries with
a .rmeta section.)

build-llvm.sh

@@ -16,7 +16,7 @@
 
 set -e
 
-: ${LLVM_VERSION:=llvmorg-14.0.0-rc2}
+: ${LLVM_VERSION:=llvmorg-14.0.0}
 ASSERTS=OFF
 unset HOST
 BUILDDIR="build"