LibJS: Use MUST instead of TRY for infallible calls to TrimString

When the spec says to call "! TrimString", we should use MUST instead
of TRY. (We were previously using TRY in order to propagate OOM errors,
but we don't care about such OOMs anymore.)

Userland/Libraries/LibJS/Runtime/GlobalObject.cpp

@@ -263,7 +263,7 @@ JS_DEFINE_NATIVE_FUNCTION(GlobalObject::parse_float)
     auto input_string = TRY(string.to_string(vm));
 
     // 2. Let trimmedString be ! TrimString(inputString, start).
-    auto trimmed_string = MUST_OR_THROW_OOM(trim_string(vm, PrimitiveString::create(vm, move(input_string)), TrimMode::Left));
+    auto trimmed_string = MUST(trim_string(vm, PrimitiveString::create(vm, move(input_string)), TrimMode::Left));
     if (trimmed_string.is_empty())
         return js_nan();
 
@@ -301,8 +301,7 @@ JS_DEFINE_NATIVE_FUNCTION(GlobalObject::parse_int)
     auto input_string = TRY(string.to_string(vm));
 
     // 2. Let S be ! TrimString(inputString, start).
-    // NOTE: We TRY this operation only to propagate OOM errors.
-    auto trimmed_string = TRY(trim_string(vm, PrimitiveString::create(vm, move(input_string)), TrimMode::Left));
+    auto trimmed_string = MUST(trim_string(vm, PrimitiveString::create(vm, move(input_string)), TrimMode::Left));
 
     // 3. Let sign be 1.
     auto sign = 1;