builtins: Add ARM Thumb1 implementation for uidiv and uidivmod

Summary:
The current uidiv supports archs without clz. However, the asm is for thumb2/arm.
For uidivmod, the existing code calls the C version of uidivmodsi4, which then calls uidiv. The extra push/pop/bl makes it less efficient.

Reviewers: jmolloy, jroelofs, joerg, compnerd, rengolin

Subscribers: llvm-commits, aemerson

Differential Revision: https://reviews.llvm.org/D27309

llvm-svn: 288710