UBSAN: shift exponent is too large

[pietroborrello]

Describe the bug Several UBSAN runtime error: shift exponent 32 is too large for 32-bit type 'unsigned int' and similar

To Reproduce Built stb according to the oss-fuzz script with CXXFLAGS='-O1 -fsanitize=address -fsanitize=array-bounds,bool,builtin,enum,float-divide-by-zero,function,integer-divide-by-zero,null,object-size,return,returns-nonnull-attribute,shift,signed-integer-overflow,unreachable,vla-bound,vptr'

UBSAN Output

$ ./stbi_read_fuzzer ./id:000116,sig:06,src:001260,time:12860161,op:havoc,rep:16,trial:1503866
INFO: Seed: 1313754043
INFO: Loaded 1 modules   (6883 inline 8-bit counters): 6883 [0x5e1b33, 0x5e3616), 
INFO: Loaded 1 PC tables (6883 PCs): 6883 [0x573228,0x58e058), 
stbi_read_fuzzer: Running 1 inputs 1 time(s) each.
Running: id:000116,sig:06,src:001260,time:12860161,op:havoc,rep:16,trial:1503866
src/stb/tests/../stb_image.h:2065:27: runtime error: shift exponent 32 is too large for 32-bit type 'unsigned int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/stb/tests/../stb_image.h:2065:27 in 
Executed id:000116,sig:06,src:001260,time:12860161,op:havoc,rep:16,trial:1503866 in 2 ms
***
*** NOTE: fuzzing was not performed, you have only
***       executed the target code on a fixed set of inputs.
***

Crashing files ubsan-shift-too-large.zip