PARQUET-679: Fix debug asserts in tests (msvc/debug build)

Fix debug asserts in tests (msvc/debug build)

Author: revaliu <revaliu@microsoft.com>

Closes #322 from rip-nsk/PARQUET-679 and squashes the following commits:

33fc780 [revaliu] PARQUET-679: refactor too long line
057a84a [revaliu] PARQUET-679: fix "vector subscript out of range" debug assert in reader and scanner tests
d50dea3 [revaliu] PARQUET-679: fix "vector iterator + offset out of range" debug assert in memory-test
diff --git a/src/parquet/column/scanner.h b/src/parquet/column/scanner.h
index 47daaed..75b08b6 100644
--- a/src/parquet/column/scanner.h
+++ b/src/parquet/column/scanner.h
@@ -104,7 +104,8 @@
   bool NextLevels(int16_t* def_level, int16_t* rep_level) {
     if (level_offset_ == levels_buffered_) {
       levels_buffered_ = typed_reader_->ReadBatch(
-          batch_size_, &def_levels_[0], &rep_levels_[0], values_, &values_buffered_);
+          batch_size_, def_levels_.data(), rep_levels_.data(),
+          values_, &values_buffered_);
 
       value_offset_ = 0;
       level_offset_ = 0;
diff --git a/src/parquet/util/memory.cc b/src/parquet/util/memory.cc
index f1fcc75..07dd20e 100644
--- a/src/parquet/util/memory.cc
+++ b/src/parquet/util/memory.cc
@@ -249,7 +249,7 @@
   total_reserved_bytes_ += total_transfered_bytes;
 
   // insert new chunks after current_chunk_idx_
-  auto insert_chunk = chunks_.begin() + current_chunk_idx_ + 1;
+  auto insert_chunk = chunks_.begin() + (current_chunk_idx_ + 1);
   chunks_.insert(insert_chunk, src->chunks_.begin(), end_chunk);
   src->chunks_.erase(src->chunks_.begin(), end_chunk);
   current_chunk_idx_ += num_acquired_chunks;