Rollup merge of #82483 - tmiasko:option-from-str, r=matthewjasper

Use FromStr trait for number option parsing

Replace `parse_uint` with generic `parse_number` based on `FromStr`.
Use it for parsing inlining threshold to avoid casting later.

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -1047,7 +1047,7 @@ pub unsafe fn with_llvm_pmb(
     // thresholds copied from clang.
     match (opt_level, opt_size, inline_threshold) {
         (.., Some(t)) => {
-            llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, t as u32);
+            llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, t);
         }
         (llvm::CodeGenOptLevel::Aggressive, ..) => {
             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 275);