Support building big-endian objects (#2382)

The JIT build_object routine currently rejects building object files
for any big-endian platform.  However, most of the object builder
code works fine for either byte order, with the exception of a small
change in the ObjectBuilderTarget::new routine.

This patch adds that change and removes the assert in build_object.

crates/jit/src/object.rs

@@ -28,10 +28,6 @@ pub(crate) fn build_object(
     dwarf_sections: Vec<DwarfSection>,
 ) -> Result<(Object, Vec<ObjectUnwindInfo>), anyhow::Error> {
     const CODE_SECTION_ALIGNMENT: u64 = 0x1000;
-    assert_eq!(
-        isa.triple().architecture.endianness(),
-        Ok(target_lexicon::Endianness::Little)
-    );
 
     let mut unwind_info = Vec::new();