Bump supported LLVM range from 10 through 15 to 11 through 16

LLVM 15 turns on the new pass manager by default, which we have yet to
migrate to so for new we pass the `-enable-new-pm-0` flag in our
llvm-passes flag.

LLVM 11 was the first version to support the `-enable-new-pm` flag so we
bump the lowest supported version to 11.

Our CI jobs are using LLVM 12 so they should continue to work despite
this bump to the lower bound.

Fixes #21936

configure.ac

@@ -554,8 +554,8 @@ AC_SUBST(InstallNameToolCmd)
 # tools we are looking for. In the past, GHC supported a number of
 # versions of LLVM simultaneously, but that stopped working around
 # 3.5/3.6 release of LLVM.
-LlvmMinVersion=10  # inclusive
-LlvmMaxVersion=15 # not inclusive
+LlvmMinVersion=11  # inclusive
+LlvmMaxVersion=16 # not inclusive
 AC_SUBST([LlvmMinVersion])
 AC_SUBST([LlvmMaxVersion])
 sUPPORTED_LLVM_VERSION_MIN=$(echo \($LlvmMinVersion\) | sed 's/\./,/')

llvm-passes

 [
-(0, "-mem2reg -globalopt -lower-expect"),
-(1, "-O1 -globalopt"),
-(2, "-O2")
+(0, "-enable-new-pm=0 -mem2reg -globalopt -lower-expect"),
+(1, "-enable-new-pm=0 -O1 -globalopt"),
+(2, "-enable-new-pm=0 -O2")
 ]