All of
"no-frame-pointer-elim-non-leaf"
"no-frame-pointer-elim-non-leaf"="true"
"no-frame-pointer-elim-non-leaf"="false"
mean "frame-pointer"="non-leaf", which is quite counter-intuitive.
llvmorg-10-init-16046-ga36ddf0aa9d accidentally broke it.
This fixes the -DLLVM_ENABLE_EXPENSIVE_CHECKS=On test:
```
*** Bad machine code: Non-flag-setting Thumb1 mov is v6-only ***
- function: pass_C
- basic block: %bb.0 entry (0x1fc9bf0)
- instruction: $r0 = tMOVr killed $r6, 14, $noreg
```